Integrated imaging circuits are known and typically include light sensitive circuitry responsive to the light intensity and wavelength of a scene to form an electronic image of the scene. The electronic images are typically provided by such circuits in the form of digital signals each representing individual pixels of the overall image.
Integrated imaging circuits of the foregoing type have been implemented in camera and video recording equipment, wherein such circuits generally form part of a larger optical information processing circuit assembly. Such assemblies not only require reliable packaging and electrical interconnect arrangements, but also require an interface to one or more optical lenses. Consequently, such requirements present unique device mounting and packaging challenges.
One known technique for mounting integrated circuits to suitable substrates involves a so-called flip chip technique, wherein bumps of solder or other conductive material are attached to the integrated circuit I/O bond pads. The integrated circuit is then mounted to a substrate with the circuit facing the substrate and with the conductive bumps in contact with corresponding bonding locations formed on the substrate. The conductive bumps are thereafter attached to the bonding locations using conventional solder reflow, thermo-compression or adhesive bonding techniques.
Flip chip technology is generally understood to provide for better interconnect integrity and reliability than many other integrated circuit interconnect techniques, and to also provide for very compact electronic assemblies, particularly when combined with conventional surface mounting techniques for discrete electronic components. It is accordingly desirable to develop useful and reliable flip chip mounting techniques for integrated imaging circuits generally, and to use such techniques to construct compact optical information processing circuit assemblies.